Pierre Ferruit

Hubble Space Telescope WFPC2 Imaging of a Sample of Early-Type Seyfert Galaxies*

We have defined a complete sample comprising all 14 Seyfert galaxies in early-type (E, S0, Sa) host galaxies with apparent magnitude mv < 14.5 mag and recessional velocity cz < 3000 km s-1. This paper presents Hubble Space Telescope (HST) imaging observations of 12 of them, the other two having been observed previously with HST. The observations are of the [O III] ?5007 and [N II] ??6548, 6583 + H? emission lines and their adjacent continua (centered near 5500 and 8000 ?). We find that all the galaxies in our sample display prominent nuclear dust features. In some objects, the dust strongly influences the morphology of the starlight and ionized gas. Despite the restriction to early-type galaxies, five (possibly six) galaxies of the 14 have a significant (if not dominant) part of their [N II] + H? emission originating in H II regions. This result supports the notion that the Seyfert phenomenon tends to be associated with ongoing star formation.

Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST)

This article summarizes a workshop held on March, 2014, on the potential of the James Webb Space Telescope (JWST) to revolutionize our knowledge of the physical properties of exoplanets through transit observations. JWSTs unique combination of high sensitivity and broad wavelength coverage will enable the accurate measurement of transits with high signal-to-noise. Most importantly, JWST spectroscopy will investigate planetary atmospheres to determine atomic and molecular compositions, to probe vertical and horizontal structure, and to follow dynamical evolution, i.e. exoplanet weather. JWST will sample a diverse population of planets of varying masses and densities in a wide variety of environments characterized by a range of host star masses and metallicities, orbital semi-major axes and eccentricities. A broad program of exoplanet science could use a substantial fraction of the overall JWST mission.

Gas and stellar dynamics in NGC 1068 : probing the galactic gravitational potential

We present SAURON integral field spectrography of the central 1.5 kpc of the nearby Seyfert 2 galaxy NGC 1068, encompassing the well-known near-infrared (NIR) inner bar observed in the K band. We have successively disentangled the respective contributions of the ionized gas and stars, thus deriving their two-dimensional distribution and kinematics. The [O III] and H beta emission lines exhibit a very different spatial distribution and kinematics, the latter following inner spiral arms with clumps associated with star formation. Strong inward streaming motions are observed in both the H beta and [O III] kinematics. The stellar kinematics also exhibit clear signatures of a non-axisymmetric tumbling potential, with a twist in both the velocity and Gauss-Hermite h(3) fields. We re-examined the long-slit data of Shapiro, Gerssen & van der Marel using a pPXF: a strong decoupling of the Gauss-Hermite term h(3) is revealed, and the central decrease of Gauss-Hermite term h(4) hinted in the SAURON data is confirmed. These data also suggest that NGC 1068 is a good candidate for a so-called sigma drop. We confirm the possible presence of two separate pattern speeds applying the Tremaine-Weinberg method to the Fabry-Perot H alpha map. We also examine the stellar kinematics of bars formed in N-body + smoothed particle hydrodynamics (SPH) simulations built from axisymmetric initial conditions approximating the luminosity distribution of NGC 1068. The resulting velocity, dispersion and higher order Gauss-Hermite moments successfully reproduce a number of properties observed in the two-dimensional kinematics of NGC 1068 and the long-slit data, showing that the kinematic signature of the NIR bar is imprinted in the stellar kinematics. The remaining differences between the models and the observed properties are likely mostly due to the exclusion of star formation and the lack of the primary large-scale oval/bar in the simulations. These models nevertheless suggest that the inner bar could drive a significant amount of gas down to a scale of similar to 300 pc. This would be consistent with the interpretation of the sigma drop in NGC 1068 being the result of central gas accretion followed by an episode of star formation.

Nuclear Gasdynamics in Arp 220: Subkiloparsec-Scale Atomic Hydrogen Disks

We present new, high angular resolution (~022) MERLIN observations of neutral hydrogen (H I) absorption and λ21 cm radio continuum emission across the central ~900 pc of the ultraluminous infrared galaxy Arp 220. Spatially resolved H I absorption is detected against the morphologically complex and extended λ21 cm radio continuum emission, consistent with two counterrotating disks of neutral hydrogen, with a small bridge of gas connecting the two. Column densities across the two nuclei are high, lying in the range 8 × 1019Ts(K) NH 2.4 × 1020Ts(K) cm-2 (Ts is spin temperature) and corresponding to optical extinctions of 0.052Ts(K) AV 0.155Ts(K) mag, with the higher column densities in the eastern nucleus. Velocity gradients are clearly visible across each nucleus, reaching 1010 ± 20 km s-1 kpc-1 in P.A. ~ 55° and 830 ± 20 km s-1 kpc-1 in P.A. ~ 270° for eastern and western nuclei, respectively. These gradients imply dynamical masses MD = 1.1 × 109( i) (E) and 1.7 × 108( i) M☉ (W), assuming that the neutral gas is distributed in two thin circularly rotating disks. We propose a merger model in which the two nuclei represent the galaxy cores that have survived the initial encounter and are now in the final stages of merging, similar to conclusions drawn from previous CO studies. However, we suggest that instead of being coplanar with the main CO disk (in which the eastern nucleus is embedded), the western nucleus lies above it and, as suggested by the bridge of H I connecting the two nuclei, will soon complete its final merger with the main disk. We suggest that the collection of radio supernovae (RSNe) detected in VLBA studies in the more compact western nucleus represents the second burst of star formation associated with this final merger stage and that free-free absorption due to ionized gas in the bulgelike component can account for the observed RSN distribution.

Detectors for the James Webb Space Telescope Near‐Infrared Spectrograph. I. Readout Mode, Noise Model, and Calibration Considerations

We describe how the James Webb Space Telescope (JWST) Near-Infrared Spectrographs (NIRSpec) detectors will be read out, and present a model of how noise scales with the number of multiple nondestructive reads sampling up the ramp. We believe that this noise model, which is validated using real and simulated test data, is applicable to most astronomical near-infrared instruments. We describe some nonideal behaviors that have been observed in engineering-grade NIRSpec detectors, and demonstrate that they are unlikely to affect NIRSpec sensitivity, operations, or calibration. These include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real test data, we show that the reset anomaly is (1) very nearly noiseless and (2) can be easily calibrated out. Likewise, we show that large-amplitude RTN affects only a small and fixed population of pixels. It can therefore be tracked using standard pixel operability maps.

A two-arm gaseous spiral in the inner 200 pc of the early-type galaxy NGC 2974: signature of an inner bar

TIGER integral-field spectrography and Hubble Space Telescope Wide Field and Planetary Camera 2 (WFPC2) imaging of the E3 galaxy NGC 2974 are used to derive the kinematics of the stellar and ionized gas components in itscentral 500 pc. We derive a numerical two-integral distribution function from a multi-Gaussian expansion (MGE) mass model using the Hunter & Qian formalism. The TIGER and published long-slit stellar kinematics, including higher-order moments, are well fitted with this self-consistent model, requiring neither the addition of a significant mass contribution from a hidden disc structure nor the presence of a central dark mass (at that spatial resolution). The data reveal the presence of a striking, highly contrasted, two-arm gaseous spiral structure within a radius of ∼200 pc, corresponding to a total mass of 6.8 x 10 4 solar masses of ionized gas. We use a deconvolved TIGER data cube to probe its kinematics at a resolution of about 0.35 arcsec FWHM. Strong departures from circular motions are observed, as well as high velocity dispersion values on the inner side of the arms. We interpret the observed gas morphology and kinematics as the signature of streaming gas flows driven by a ∼540-pc diameter bar with Ω p = 700 ′ 100 km s - 1 kpc - 1 . This hypothesis is strongly supported by the predictions of a density wave model. This model predicts that the bar should lie at about 35° from the line of nodes, and implies gas inflow towards the central ∼50 pc. The quadrupole perturbation due to this bar is estimated to represent less than 2 per cent of the underlying gravitational potential (a maximum torque of about 10 per cent), explaining the lack of a direct detection via broad-band photometry in the visible. Despite its weakness, the inner bar of NGC 2974 may be able to drive some gas within a 10-pc radius. We suggest that the presence of such inner bars might be more common among early-type disc galaxies than is generally thought, and that deep high-resolution emission-line imagery may be the best way to detect such structures.

Spatially Resolved Ultraviolet Spectra of the High-Velocity Nuclear Outflow of NGC 1068*

We present ultraviolet emission-line maps of the narrow-line region (NLR) of NGC 1068. The maps span 115-318 nm, the biconical ionization cone, and several posited jet-ISM interactions, and the compact knots whose optical spectra we reported previously resemble kinematically the quasar associated absorption line systems. Across the NLR, we find that ultraviolet flux ratios are consistent with photoionization, not shock excitation, even for gas blueshifted abruptly to 3000 km s-1 relative to galaxy systemic velocity or for gas projected near the radio jet. The knots may be radiatively accelerated, photoablated fragments of molecular clouds.

Probing unexplored territories with MUSE: a second generation instrument for the VLT

The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph under preliminary design study. MUSE has a field of 1x1 arcmin2 sampled at 0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The simultaneous spectral range is 0.465-0.93 μm, at a resolution of R~3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. This makes MUSE a unique and tremendously powerful instrument for discovering and characterizing objects that lie beyond the reach of even the deepest imaging surveys. MUSE has also a high spatial resolution mode with 7.5x7.5 arcsec2 field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain diffraction limited data-cubes in the 0.6-0.93 μm wavelength range. Although the MUSE design has been optimized for the study of galaxy formation and evolution, it has a wide range of possible applications; e.g. monitoring of outer planets atmosphere, environment of young stellar objects, super massive black holes and active nuclei in nearby galaxies or massive spectroscopic surveys of stellar fields in the Milky Way and nearby galaxies.

Overview of the near-infrared spectrograph (NIRSpec) instrument on-board the James Webb Space Telescope (JWST)

The James Webb Space Telescope (JWST) mission is a collaborative project between the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA) and the Canadian Space Agency (CSA). JWST is considered the successor to the Hubble Space Telescope (HST) and although its design and science objectives are quite different, JWST is expected to yield equivalently astonishing breakthroughs in infrared space science. Due to be launched in 2013 from the French Guiana, the JWST observatory will be placed in an orbit around the anti- Sun Earth-Sun Lagrangian point, L2, by an Ariane 5 launcher, provided by ESA. The payload on board the JWST observatory consists of four main scientific instruments: a near-infrared camera (NIRCam), a combined mid-infrared camera/spectrograph (MIRI), a near-infrared tunable filter (TFI) and a nearinfrared spectrograph (NIRSpec). The instrument suite is completed by a Fine Guidance Sensor (FGS). Besides the provision of the Ariane 5 launcher, ESA, with EADS Astrium GmbH (D) as Prime Contractor, is fully responsible for the funding and the furnishing of NIRSpec and, at the same time, for approximately half of MIRI costs through special contributions from the ESA member states. NIRSpec is a multi-object, spectrograph capable of measuring the spectra of about 100 objects simultaneously at low (R=100), medium (R=1000), and high (R=2700) resolutions over the wavelength range between 0.6 micron and 5.0 micron. In this article we provide a general overview of its main design features and performances.

Hubble Space Telescope/Faint Object Spectrograph Spectroscopy of Spatially Resolved Narrow-Line Regions in the Seyfert 2 Galaxies NGC 2110 and NGC 5929*

We present the results of UV and optical Hubble Space Telescope/Faint Object Spectrograph spectros- copy of bright, extranuclear regions of line emission in the Seyfert galaxies NGC 2110 and NGC 5929. We have obtained spectra of the brightest region of the ii nuclear jet ˇˇ of NGC 2110 (75 pc from the nucleus) and of the southwest emission-line cloud of NGC 5929 (90 pc from the nucleus), in the G130H (1090¨1605 G190H (1570¨2310 G400H and G570H (4570¨6820 con—gurations. Ae ), Ae ), (3235¨4780 Ae ), Ae ) The observed line ratios are compared with the predictions of the two component (matter- and ionization-bounded, MB-IB), central source photoionization models of Binette, Wilson, & Storchi- Bergmann and of the fast, photoionizing (ii autoionizing ˇˇ) shock models of Dopita & Sutherland. In both objects, the signi—cant reddening inferred from the Balmer line ratios and/or its uncertainty limit the utility of the ultraviolet carbon lines C IV j1549 and C III) j1909 for discrimination between the central source and shock-induced photoionization mechanisms. In NGC 2110, shock)precursor models with a shock velocity of ^400 km s~1 provide a better match to the data than the MB-IB models. However, given the simplifying assumptions made in the latter models, photoionization by a central source cannot be ruled out. We investigate whether photoionizing shocks in the emission-line region of NGC 2110 can power the extended, soft X-ray emission north of the nucleus and —nd that shock veloci- ties higher than 500 km s~1 are required. In NGC 5929, the MB-IB models have problems reproducing the strengths of the neon lines, while shock)precursor models with a velocity ^300 km s~1 provide a good match to the data. For both galaxies, the emission-line powers and volumes of the ionized gas inferred from observations imply that both the preshock density and magnetic parameter